Shock absorber



May 25, w43 J. CHUDNER 2,320,221

sH'ocK ABsoRBER Filed Jan. 8, 1942 A'llnu'o'" l 25 INVENTOR 50 Jseph Chudner 4 1* 29 BY r mm, MVM @LM ,7 ATTORNEYS Patented May 25, 1943 UNITED STATES PATENT @Fl-TICE 7 Claims.

This invention relates to a device for stopping the rapidly moving parts of a machine with a cushioning and shock-absorbing effect to assure a proper and e'cient operation of the machine.

More particularly the invention relates to a stop mechanism or shock absorber of the type disclosed in United States Letters Patent No. 2,167,474, granted to me July 25, 1939.

The principal objectof theinvention is the provision of a device of the indicated character which will be of substantially improved and eicient design for' the intended purposes.

The nature of the invention and its distinguishing features and advantages will appear when the following specification is read in connection with the accompanying drawing, in which Fig. 1 is a side view of part of a buttonhole stitching machine selected to illustrate the invention shown applied thereto by way of example;

Fig. 2 is a View looking at one side of the device embodying the invention, parts being broken away to show certain features;

Fig. 3 is a view looking at the the device;

Fig. 4 is a sectional View taken on the line 4-4 of Fig. 5 and looking in the direction indicated by the arrows;

Fig. 5 is asectional view taken on the line 5--5 of Fig. 3 and looking in the direction indicated by the arrows;

Fig. 6 is a sectional view taken on the line 6 6 of Fig. 4 and looking in the direction indicated by the arrows;

Fig. 7 is a view in elevation of the group of shock-absorbing springs and the abutment earried by and associated therewith; and

Fig. 8 is a sectional View taken on the line 8-8 of Fig. 7 and looking in the direction indicated lby the arrows.

The invention is shown, by way of example, applied to a buttonhole stitching machine of a standard type, part of which is shown in Fig. l. A machine of this character includes a standard I and a suitable means supports a transmission shaft II on which is secured a driven element or pulley I2. Associated with the pulley is a stop mechanism which includes a stop bar or rod I3 which is operable so that one end thereof may be moved into and out of a notch I4 in a cam I5.

As is well known, in making buttonholes it is desirable to have certain parts of the machine operate as rapidly as possible and then stop quickly. To prevent any overrunning and over- Working of parts and the impact or jarring resultopposite side of ingfrom stopping the same, certain cushioning and shock-absorbing means is necessary to resist these forces proportional to the degrees in which they occur. The means hereinafter described serves adequately for carrying out the results looked for. The driven element or pulley I2 consists of two parts or sections, a section I6 and a section I'I. The vsections are of hollow construction to provide a circular space I8, and section I6 has a central inner hub portion I9 and an outer hub portion 20 in axial alinement with the portion I3 and in continuation thereof but of reduced diameter to .provide a shoulder 2l. The section Il has a central hub 22 adapted to loosely surround the hub portion I9. This section Il also carries locating pins 23 receivable in holes, respectively, in the section I6 in order to properly associate the section I'I with the section IB and also for the purpose of alining tapped. holes in the section I6 which receive certain fastening elements or screws 24, respectively, extending through plain holes in the section II. The section IB is fixed to the shaft II by a cross pin 25 which extends through the shaft II, its opposite ends extending into the hub portion I9, as shown .in Figs. 2, 4 and 5. The section I6 has a groove 26 to accommodate a belt (not shown) by which the element or pulley I2 is rapidly rotated or driven. The section I6 also has an arcuate slot 2l therein. The cam I5 has a round hole therein in order to loosely fit on the hub portion 20, as shown in Fig. 3. The cam I5 also has a pin 28 which pro'- jects through the slot 21 into a hole 29 in an abutment 3U arranged within the space I8. Resilient means 3| is employed in conjunction with the abutment 3D and a lug 32 integral with or secured to the section I'I, as in the present instance by pins 33. The means 3I consists of a group of arcuate leaf springs 34 laid one Within another and of progressively different lengths. The innermost spring 34 has the opposite ends thereof respectively in engagement or contact withithe opposite sides, respectively, of the abutment 3U, and the ends 35 of the innermost spring 34 being rounded to receive lateral projections 36 against which said ends 35 bear. The group of springs 34 and the abutment 30 constitute a unit in which the abutment is held in place by the ends 35. The group of springs 34 is arranged within the space IB in the pulley section I6 and is loosely arranged on the hub 22 of the section I'I, as shown most clearly in Figs. 4 and 5.

On reference to Figs. 4 and 7, it will be apparent that one end of each of the springs 34 abuts against one side of both the lug 32 and the abutment 30, and that the opposite end of each spring 34 is progressively spaced from the other side of both the lug 32 and the abutment 30, with the exception of the innermost spring 34 whose ends 35, as pointed out above, contact the opposite sides, respectively, of the abutment 30 and also the lug 32.

From the foregoing -it will be apparent that all the parts rotate together in the rotation of the pulley I2 in driving the shaft II. When it is desired to arrest and stop the movement of the pulley I2 after completion of a piece of work, such as the stitching of a buttonhole, the rod I3 is moved upwardly into a position to be engaged by the cam I5 in such a manner that the upper end of the rod I3 enters the notch I4. The pulley I 2 will continue to move with the shaft I I, as indicated by the arrows in Figs. 2, 3 and 4, while the abutment 30 will be held stationary by reason of the pin 28 carried by the cam I5, since the latter will be held stationary by the rod I3. The impact or torsional strain resulting from the sudden stopping of the cam I5 will be resisted by reason of the fact that the lug 32 will be coacting with or exerting pressure on one end of one or more of the springs 34, while the opposite end of each of said springs 34 will abut against the abutment 30 held stationary by the pin 28. In other words, the lug 32 will be forced against one end 35 of the innermost spring flexing Ait outwardly which in turn acts on the end of the next spring and so on causing the staggered ends of the springs 34 to come into action seriatim, or in such manner as to resist the shock of the sudden stopping in proportion to the degree of the shock. In this manner the rapidly moving parts of the machine will be stopped almost instantly with a cushioning and shock-absorbing elect and, therefore, assure a proper and efficient operation of the machine.

When the rod I3 is withdrawn by lowering the same out of the notch I4, at which time the parts of the device have assumed their normal relationship, the stitching machine may again be operated for the purpose of stitching another buttonhole as will be understood.

I claim:

1. In a stop mechanism, a rotary element, an abutment arranged on said element so as to rotate therewith and also to be held stationary with respect thereto, means to engage said abutment to hold it stationary, and resilient means loosely mounted with respect to the rotary element and which co-operates with said rotary element and the abutment when the latter is held stationary to yieldingly resist and ultimately stop the rotary movement of said element.

2. In a stop mechanism, a rotary element, an abutment arranged on said element so as to rotate therewith and also to be held stationary with respect thereto, means to engage said abutment to hold it stationary, a xed lug on said element, and resilient means loosely mounted with respect to the rotary element which co-operates with said lug and the abutment when the latter is held stationary to yieldingly resist and ultimately stop the rotary movement of said element.

3. In a stop mechanism as set forth in claim l wherein said resilient means consists of a group of arcuate leaf springs laid contactually one within another.

4. In a stop mechanism as set forth in claim 2 wherein said resilient means consists of a group of arcuate leaf springs laid one within another and of progressively diierent lengths and one end of each of said springs abutting said abutment at one side so that sa-id lug may coact with the other end of one or more oi the springs in proportion to the degree of torsional force exerted by said element.

5. In a stop mechanism, a hollow rotary element constructed of two sections, an abutment arranged within said element so as to rotate therewith and also to be held stationary with respect thereto, a group of arcuate leaf springs laid one within another disposed -inside of said element, said group being loosely arranged within said. element, one end of each one of said springs abutting said abutment, and means on said element disposed to coact with one or more of the remaining ends of the springs -in proportion to the degree of torsional force exerted by said element while said abutment is held stationary.

6. In a stop mechanism, a hollow rotary element constructed of two sections, an abutment arranged within said element so as to rotate therewith and also to be held stationary with respect thereto, a group of arcuate leaf springs laid one within another disposed inside of said element, said group being loosely arranged within said element, one end of each one of said springs abutting said abutment, means on said element disposed to coact with one or more of the remaining ends of the springs in proportion to the degree of torsional force exerted by said element while said abutment is held stationary, and means engageable with said abutment to hold it stationary and also disengageable to release it for rotation with said element.

7. In a shock absorber, a group of arcuate leaf springs arranged one within another, an abutment held in place by the opposite ends of the innermost one of the springs, said abutment having provision whereby it may be engaged to hold it stationary to resist the springs, and a movable part which is resisted by said springs when the latter are resisted by said abutment.

JOSEPH CHUDNER. 

